Watts per hour isn’t a thing. Watts is already a measurement of rate. 67 watts, running for 24 hours, is 1.608 kilowatt-hours.

The rest of your math checks out, assuming no hidden “distribution” or “transmission” fees (like I have).

For anyone unaware, the gallon size of condiments (mayo, ranch dressing, hot sauce, etc) is typically for food service. IOW, restaurants and the like.

That said, there’s nothing stopping individuals from getting it, so the point is still valid.